Electric switch



Jan, 13, 1925. 1,523,054

.1. A. CRABTREE ELECTRIC SWITCH Filed March 20, 1924 2 sheets-sheet d Jan, .13, 1925.

Y 1,523,054 J. A. CRABTREE ELECTRIC SWITCH Filed March 20, 1924 2 Sheets-Sheet 2 Patented Jan. 13, 1925.

irse sr Maaate JOHNn A. CRABTR-EE, OF ERDINGTON, BIRMINGHAM, ENG-LAND.

ELECTRIC SWITCH.

Application filed March 20, 1924. Seria] No. r700,660.

To all whom t may conce/rn.'

Be it known that I, JOHN AsHwoRTH CRATREE, a subject of theA King of Great Britain, residing at 1?0 Grphanage Road,

Erdington, Birmingham, England, have invented certain new and useful Improvements in oriRelating to- Electric Switches, of which the following is a specification.

rIhis invention comprises certain impro'i'fements in Vor relating to electric switches, which improvements are particularly applicable, but not restricted, to switches of the tumbler type. For convenience in description in the following specification, the several axes of the switch mechanism are defined with reference to their altitude, and in the case of a tumbler switch,

this altitude' has reference' to the back of the switch base. rlhe definition of an axis asbeinglocated below orabove another axis or position thus indicates that the axis in question is respectively nearer to or farther away from the back of the switch base than thefpoint or position in relation to which it is defined. The invention is not, however, strictly limited to these conditions, as ob` viously precisely the sameaction might be mounted without a base, and .it is, therefore, desired that the present specification be construed accordingly..

According to the pre-sent invention,n I provide a pivoted operating member which extends downwardly and is adapted to cooperate with the Contact member at a position below the pivotal axis'of'the latter during-.the whole or` a :part of the movement, the arrangement being such that the point of co-operation of the operating member with the contact member passes across said pivotal axis beyond the latter ,in the movements of the switch. The pivotal axis of the contact member may be fixed or movable.V In the case of a tumbler switch, the said operating member may constitute a tumbler dolly or a part rigid therewith, or it may constitute a part capable of a limited degree of articulation in relation to the tumbler dolly. The axis of the contact arm may in one embodiment be coupled by a link to a fixed axis s0 that by virtue of the said link the axis 0f the contact arm is capable of substantially vertical movement to accommodate the action of the switch mechanism;

In order that this invention may be clearly understood and readily carried into practice, reference may be had to the appended explanatory drawings, in which- Figure l isa sectional elevation of a tumbler switch embodying the present invention.

Figure 2 is a sectional elevation from an aspect at right angles to that of Figure l of the switch shown in the figure last men* tioned.

Figure 3 is a view similar to Figure l showing a modification.

Figure l is a similar view to Figure l but showing a further modification.

Figure 5 illustrates the modification shown in Figure 4 but with the switch in the open position.

Figure 6 is a similar view to Figure fl but showing a still further modification.

In a convenient embodiment of the present invention as applied to a tumbler switch, the tumbler dolly a ismounted in the bridge Z) secured ,to the base 7c and furnished with a depending operating portion c which is pivoted to the Contact member (Z at d1. The contact member CZ extends upwardly from its axis all of pivotal connection with the depending operating member'to a point at which said contact member is pivoted at e to a transversely locatedllink The said link extends to apoint at which it is pivoted to move about a' fixed axis. At this point it may be mounted upon ears g' or other bearing members provided upon the bridge b or base. Between the axis @of connccticnof the contact member l with the link f and the axis j of the dolly c, a compression spring element is incorporated. This may consist of a spring la encircling a rod z' pivoted at the axis y' of the operating dolly a and forked to co-operate with the floating' pivot el of the link f. When, therefore, the axis Z1 of pivotal connection of the depending operating portion c with the contact arm is dis-placed in the process of operating the switch it is carried across the plane passing through the axes y' and e of the operating member a and contact arm (Z, this action being permitted by the oscillation of the link f and contraction of the spring element k between the axes e and y', of the contact arm and ,tumbler dolly.

Figure 3 illustrates a modification in which the spring tlenciroles a rod 1 which is pivoted to oscillate about the axis j of the .tumbler dolly a, the said rod ell-passing contact arm.

through a perforation in the lug f1 in the A tumbler switch constructed according to the present invention is obviously `of the so-called underslung type, that is to say, the chord of the arc oi movementvot' the moving contact member is substantially parallel with the back ot' the switch base.V

A tumbler switch, when according to the underslung arrangement as shownY and oi the one-way type, is such that whenit is in position upon a. wall with the fixed contacts in the uppermost halt` of the base, that l part of the tumbler dolly which is pressed bv the hand has to be displaced downwardly in the process oi closing the switch.

The depending part of the operating member being adapted-to extend downward ly below the axis of the contact member, which latter is located at level between its axis of connection with the operating member and the axis of the latter, has the result that the arc of movement of the movable contact portion is magnified relatively in relation to the movement ot the tumbler dolly so that a measure of rapidity ot make and break is thereby obtained.

In the construction defined in the forelgoing particular description it will be noted that thearrangement is such that lin theV Y event of the spring failing to act, the contact member may be displaced by a partial A ating lever pivota'll-y mounted on the base and connected directlytolthe movable contact 4at a point'between the base andtheV Y pivot point ot the movable contact, whereby to positively move the movable contact into and out ot contact with the stationary con'- tact.. f

2. An apparatus of the class described comprising a base, a. stationary contact mounted thereon, an operating lever zpivotally mounted on the base, alink pivotally` connected tothe base, and amovable contactmember pivotally carried by the same adjacent to the tree 'end thereof, said operating lever being Vpositively connected to the movable contact member at a point between the base and the pivot point of the movable contact. 1

3. An apparatus. of the class described comprising a base,V a Y stationary contact mounted thereon, a link pivotally carried by the base, a movable contact pivotally carried by the link adjacent to the free endithereot, an operating lever pivotally mounted on the base and positively connected' tothe Vmovable contact ata point between the base and the pivot point of the movable contact,and means positioned between the base and the free end of the link to urge the movable contact into either lot two extreme'positions when said Contact is Vmoved by the lever to a point tol oneside or the other of the center i' line through thejpivot points of Vthe operating lever and its pointoil connection with the pivoted contact.

In testimony whereof I hereunto aiiix mysignature.

Vaaonanfrnnn 

